Work statistics for sudden quenches in interacting quantum many-body systems. (arXiv:1907.06285v1 [quant-ph])

Work in isolated systems, defined by the two projective energy measurement
scheme, is a random variable whose the distribution function obeys the
celebrated fluctuation theorems of Crooks and Jarzynski. In this study, we
provide a simple way to calculate the work distribution associated to sudden
quench processes in a given class of quantum many-body systems. Due to the
large Hilbert space dimension of these systems, we show that there is an energy
coarse-grained description of the exact work distribution that can be
constructed from two elements: the level density of the initial Hamiltonian,
and the strength function, which provides information about the influence of
the perturbation over the eigenvectors in the quench process. We also show how
random Hamiltonian models can be helpful to find the energy coarse-grained work
probability distribution and apply this approach to different spin-$1/2$ chain
models. Our finding provides an accurate description of the work distribution
of such systems in the cases of intermediate and high temperatures in both
chaotic and integrable regimes.